Nothing, because it won't compile. Unless you mean "compiler output", in which case: errors. Int is not a valid type (C++ is case sensitive so "int" does not mean the same as "Int") l (lowercase L) is not defined so this will also throw an error. Also there is a semicolon missing after the ++. If the errors are fixed (and l really means n), then the output will be 1,2,3,... until n<0, which will be when the most significant bit of n is 1, which depends on sizeof(int). If int is four bytes on your system, the loop will terminate when n=0x80000000.
Unless of course Int isn't an error, and is actually typedef'd somewhere. If Int is typedef unsigned int, then the loop will never terminate (because n<0 is never true for unsigned variables), but the compiler should throw a warning about this.